One of the most memorable parts of AGDQ last year wasn’t a typical speedrun: instead, it a demonstration of Tetris the Grand Master, an incredibly challenging Japanese arcade variant of Tetris played by jaw-droppingly talented individuals. This year, AGDQ offered a similar showcase of the rhythm game Stepmania.

Stepmania is an open-source rhythm game engine based around the core gameplay of the Dance Dance Revolution series: directions scroll on screen, and the player must press the corresponding keys to match them with perfect timing. Being an open-source project, a community of players and modders have added numerous custom songs, input charts, graphics, effects, and challenging alterations to the game.

Some of these songs and modifications are absurdly difficult, but to devoted Stepmania players, these challenges aren’t just made to be surmounted, but dominated in the most impressive ways possible.

You'll find the most amazing Stepmania feat at the 23:00 mark, where a player who goes by the name Staiain hits a peak of 30 notes per second. That's 30 individual keystrokes, most of which he hits within a 45 millisecond window of accuracy. His hands are moving so fast it looks like he's shaking the camera.

The players and commentators explain things a bit more in the roughly half-hour showcase of the game, complete with a keyboard cam to show just how fast the players’ fingers have to move to keep up with the constant flood of arrows coming at them.